1. Field of the Invention
The present invention relates to a semiconductor memory device and a USB memory device using the same.
2. Description of the Related Art
A USB memory in which a flash memory and a USB (Universal Serial Bus) connector are integrated has characteristics that it is excellent at connectivity with various devices, writability of information, portability, and so on, and further has a large storage capacity in itself. The USB memory becomes common rapidly from the points as stated above, as storage media of a PC (Personal Computer), peripheral devices thereof, a communication device and an audio player in portable type, an HDD (Hard Disk Drive) recorder, a DVD (Digital Video Disk) recorder, and so on. The USB memory generally has a structure in which a USB connector component and a circuit board on which a flash memory is mounted are connected to be integrated.
The USB connector component has a structure in which components holding a metal terminal as an input/output terminal by a resin board are arranged inside of a metal case (USB connector case) to be plugged into a USB port. On the other hand, electronic components such as a capacitor, a resistance, a quartz oscillator are surface mounted on the circuit board together with an IC package including a memory element and a controller element. It is impossible to miniaturize the USB memory connecting and integrating those less than a size in which a size of the USB connector component is added to a substrate size mounting each component. In particular, the IC package is larger than the other components, and therefore, the size thereof prevents the miniaturization of the circuit board, and further, the miniaturization of the USB memory.
The USB memory is used by plugged into the USB ports of the PC, the peripheral devices thereof, and so on. Consequently, a connecting portion and so on are easy to be damaged only by adding a slight force in an unnecessary direction if the USB memory in itself is large. It is therefore studied to make the USB memory miniaturize further more. For example, a USB memory in which an input/output terminal of a USB connector is provided at one end side of a circuit board, and a memory element and a controller element are mounted on a terminal providing surface of the circuit board is described in JP-A 2003-331249 (KOKAI). However, the memory element and the controller element are mounted as an IC package, and a structure as same as a memory card is adopted. It is difficult to fully miniaturize the conventional USB memory, and the USB memory as described above is also the same.
A USB memory in which an input/output terminal of a USB connector is arranged at an upper surface side of a circuit board arranged inside of a USB connector case, and a semiconductor device having a memory element and a controller element is arranged at an lower surface side of the circuit board is described in a US 2004/0153595 A1. Here, a multi chip package is created by mounting the memory element and the controller element on a substrate, and this is mounted at the lower surface side of the circuit board on which the input/output terminal is provided. It is inevitable that a thickness and a size of the multi chip package in itself including the memory element and the controller element become large. Consequently, there is a possibility that the size of the multi chip package in itself becomes an obstacle to mount it on the circuit board arranged inside of the USB connector case.